Police and SWAT teams moved in, and about two dozen rioters were arrested, Toledo Police Chief Michael Navarre said. He said he expected 30 to 40 arrests by the end of the day.

Toledo Mayor Jack Ford declared a state of emergency and asked for 50 highway patrol officers to reinforce Toledo police. A curfew came into effect at 8 p.m. for people "roaming around the streets," he said.(Watch neo-Nazi protests turn violent)

He also blamed gang members for the violence,saying it turned into "exactly what they wanted," referring to the Nazi group. Ford said he had appealed to the community Friday night to ignore the Nazi march.

It's not clear why the National Socialist Movement chose north Toledo for its march, said Ford, himself African-American. "It is not a neighborhood where you have a lot of friction in the first place," he said.

The NSM promotes itself as America's Nazi Party and said that it was protesting black gangs, which it claimed were harassing white residents. The group said it had received support from Toledo's white citizens and community activists.

A spokesman for the group, Bill White, blamed the riot on Toledo police, saying the police intentionally changed the group's march route to make it collide with a counter-demonstration.

About 20 members from both the International Socialists Organization and One People's Project showed up, and some handed eggs to African-American residents to throw at the Nazi marchers, White said.

Ford said that scenario was likely.

"Based on the intelligence we received, that's exactly what they do -- they come into town and get people riled up," Ford said. "I think that's a very common technique."

The Nazi march was called off, and none of the National Socialist Movement group's 80 members who showed up to participate was arrested, White said.

The violence was contained to a six- or eight-block area in the north Toledo neighborhood, she added.

At least 150 officers from various units -- some on horseback, bicycles and in riot gear -- were on the scene. The city's police chief said his officers showed "considerable restraint" after being pelted with rocks and bottles for "considerable hours."

"We could have made a couple hundred arrests," he said.

Ruiz-Krause blamed the mayhem on a disorganized group of the community's youth.

Most of the violence happened when residents, who had pelted the Nazi marchers with bottles and rocks, took out their anger on police, said Brian Jagodzinski, chief news photographer for CNN affiliate WTVG.

Video showed crowds at around 2:25 p.m. using bats to bring down a wooden fence as looters broke into a small grocery store.

"The crowd was very ... extremely agitated at the police ... for doing this [making arrests in] the community when they should be doing this to the Nazis," Jagodzinski said.

Around 3 p.m., crowds of young men pelted the outside of a two-story residence with rocks, smashed out the windows with wooden crates, ran inside and threw out the furniture and lamps from the upper-level windows to the sidewalk below. No police were on the scene.

About 10 minutes later, the building's second story was in flames as a crowd of people watched.

When police arrived, they used pepper spray on counter-demonstrators and shot tear gas containers into the crowd, Jagodzinski said.

He added that his news van and a police car had windows smashed and doors bent back.

When the violence broke out, the Nazi marchers returned to their headquarters, White said.

A statement from the National Socialist Movement said Toledo city officials had said they would not issue a permit for the group's march. The group said it did not seek a permit, because it didn't ask for "special accommodations."

"We are not asking that roads be closed; we are not asking that sidewalks be closed; we are not asking for additional police protection," White said in the statement. "All we are saying is that we will have a few people walking down the street making a statement about an issue the City is refusing to address.

"And if the City interferes with or unreasonably burdens our ability to do so, then they will answer for their behavior in court," the statement added.